Level



Sept. 11, 1945 F. J. ALLGEO LEVEL Filed July 20 1943 2 Sheets-Sheet l//%lIIV///////////////,

INVENTOR Fred J HZZgeo m r r A Sept. 11, 1945- F. J. ALLGIEO LEVEL FiledJuly 20, 1943 2 Sheets-Sheet 2 INVENTOR Fred J. flllgeo arr-rs PatentedSept. 11, 1945 UNITED STATES PA'lEll'l OFFICE LEVEL Fred J. Allgeo, SanFrancisco, Calif.

Application July 20, 1943, Serial No. 495,461

6 Claims.

This invention is directed to, andit is an object to provide, animproved mechanical gravity actuated level arranged to indicatedeviations from a perpendicular or horizontal plane.

Another object of the invention is to provide a gravity actuated level,of the pendulum-type, which is constructed so that the friction error isnegligible whereby accurate readings may be obtained.

A further object is to provide a level of the type described which isarranged for easy reading.

A still further object is to provide a level which, due to itsconstruction, is adaptable to many and various uses, both commercial andmilitary.

It is also an object to provide means whereby the scaled, transparentdome which the device includes, may be adjusted both vertically andhorizontally so that an initial accurate setting can be obtained beforeeach use of the device.

A further object of the invention is to produce a simple andinexpensivedevice, and yet one which will be exceedingly effective for the purposefor which it is designed.

These objects I accomplish by means of such structure and relativearrangement of parts as will fully appear by a perusal of the followingspecification and claims.

In the drawings similar characters of reference indicate correspondingparts in the several views:

Figure l is a top plan of the device with the transparent scaled domeand its supporting plate partly broken away.

Figure 2 is a sectional elevation of the device.

Figure 3 is an enlarged fragmentary cross section on line 3-3 of Fig. 1.

Figure 4 is a fragmentary bottom plan view of the cross hair arrangementas centered in the bottom of the device.

Figure 5 is an enlarged fragmentary section on line 5-5 of Fig. 2.

Referring now more particularly to the characters of reference on thedrawings, the level comprises an initially open topped box l which isrectangular in plan and includes opposed, parallel and upstanding sides2 and a bottom 3 at a right angle to said sides.

A cover plate 4, symmetrical to the box, is mounted thereon as a lid andincludes a relative- 1y large, centered opening 5 of circular form intowhich the lower edge of a substantially hemispherical dome 6 is secured.This dome is transparent and is scaled as at l in equally spacedcircumferential and radial lines, said lines representing predetermineddeviations in degrees reading from the top center point P of the dome.Any preferred scaling can be employed.

The plate 4 is supported at the corners for vertical adjustment byindividualyvertically disposed adjustment screws 8, each of whichinclude a horizontally grooved head 9 into which the cover engages inloose play relation horizontally to permit of lateral adjustment of thecover, as will hereinafter appear. A knurled actuating disc If: on eachscrew 8 projects beyond the corners of the box for access.

The cover plate 4 is laterally adjustable by suitable means such ashorizontal set screws ll threaded through brackets 12 on the sides ofand projecting above the box, said screws l l engaging adjacent edges ofsaid plate.

By means of screws 8 and H the plated, and consequently dome 6, can beadjusted in vertical as well as horizontal position.

The gravity actuated, universally mounted, pendulum assembly which thedevice includes, comprises the following:

A cross beam l3 extends between opposite sides of the box, centrallybetween the other sides, and is supported at its ends by adjustableneedle bearings M; such beam l3 being slottedthrough from top to bottom,as at l5, for substantially its full length. A semi-circular pendulum l6of skeleton protractor form and having a straight top bar "I l, isdisposed in the box with said bar in slot l5 and in clearance relationto adjacent portions of beam 13. Needle bearings l8 are mounted on beamis centrally of its end and on opposite sides to engage and supportcorrespondingpo tions of bar I! at a point equidistant between its ends.

The needle bearings M as well as needle bearings I8 are in verticalplanes intersecting the top center point P of the scaled dome 8, and arein the same horizontal plane relative to each other.

The pendulum includes a pendulum weight l9 centered at the bottomthereof. .An upstanding pointer is mounted in centered relation on thebar I1, and projects upwardly to a termination adjacent and r ading onthe scaled dome 6. A spider supported, degree graduated ring 2|,concentric to the pointer 25, is mounted on and supported by the latterintermediate its ends; the ring being of a diameter to clear the innersurface of said dome at all times. Either the pointer 20 or ring 2! canbe read on the sealed dome.

The pointer 22 is tubular, as at 22, and open ended, the lower endopening through the bar I! as clearly shown in Fig. 5. The pendulumweight I9 is formed with a bore 23 alined with tubular pointer 20, and atransparent plate 24 marked with cross hairs is seated in the bottom 3of the box over an aperture 26. The point of intersection of said crosshairs 25 is in vertical alinement with the center point P at the top ofthe dome. Feet 21 support the box I so that light can pass thereunder.

In use the box I is disposed on the object whose level is to be checked,and the device is then read, selectively, by reading pointer 20 againstthe scaled dome, or reading scaled ring 2| against the scaled dome, orby sighting through tubular pointer 20 and bore 23 in Weight l9 to readagainst the cross hairs 25.

As a convenience for the user, a small telescope T may be mounted on thelevel alongside the box I adjacent the top thereof.

From the foregoing description it will be readily seen that I haveproduced such a device as substantially fulfills the objects of theinvention as set forth herein.

While this specification setsforth in detail the present and preferredconstruction of the device, still in' practice such deviations from suchdetail may be resorted to as do not form a departure from the spirit ofthe invention, as defined by the appended claims.

Having thus described my invention, what I claim as new and useful anddesire to secure by Letters Patent is:

1. A mechanical gravity actuated level comprising an initially opentopped box, a hemispherical dome mounted on the box at the top andopening to the interior thereof, said dome being transparent and havinga scale thereon, a cross beam extending from side to side of the box,bearings supporting said beam at opposite ends for rotation about itslongitudinal axis, a pendulum including an upstanding pointer and adepending weight, and bearing means pivotally mounting said pendulumintermediate its ends on said beam for swinging movement in a planelengthwise of thelatter, the axis of the beam and the axis of thependulum being atarightangle to each other in a horizontal plane andintersecting at the center point of the dome; there being a scaled ringconcentrically surrounding and supported by the pointer intermediate itsends, said ring being of substantial diameter and the periphery of thering being closely adjacent the inner surface of said dome.

2. A mechanical gravity actuated level comprising an initially opentopped box, a hemispherical dome mounted on the box at 'the top andopening to the interior thereof, said dome being transparent and havinga scale thereon, a cross beam extending from side to side of the box,bearings supporting said beam at opposite ends for rotation about itslongitudinal axis, said beam being slotted through from top to bottomfor substantially its full length, a semi-circular pendulum having astraight top bar and including a pointer upstanding from the bar and aweight at the-bottom of the semi-circular portion, the top bar beingdisposed lengthwise in said slot in clearance relation, and bearingmeans pivoting the bar centrally of its ends in the slot for swingingmovement in a plane lengthwise of the latter, the axis of the beam andthe axis of the pendulum being at a rigid angle to each other in ahorizontal plane, and intersecting at the central point of the dome; thepointer being tubular and open at both ends, the lower end of thepointer opening through said bar, the weight having a bore alined withthe tubular pointer, and a transparent pane having cross-hairs markedthereon disposed over an aperture in the bottom of the'box, the point ofintersection of the. crosshairs being Vertically alined with the topcenter point of the dome.

3. A mechanical, gravity actuated level comprising an initially opentopped box, a transparent scale-marked hemispherical dome disposed ontop of the box, and means mounting said dome on the box for vertical orhorizontal adjustment, selectively; said means including a cover platesupporting the dome, vertically adjustable screws supporting the plateadjacent its corners, and horizontally adjustable set screws engagingthe edges of said plate between said corners. V

4. A mechanical. gravity actuated level comprising an initially opentopped box, a transparent scale-marked hemispherical dome disposed ontop of the box, and means mounting said dome on the box for vertical orhorizontal adjustment, selectively; said means including a cover platesupporting the dome, vertically adjustablescrews supporting the plateadjacent its corners, and horizontally adjustable set screws engagingthe edges of saidv plate between said corners, the ver-' ticallyadjustable screws being connected to said plate as to limit relativevertical movement but to permit of a certain horizontal movement.

5. A mechanical, gravity actuated level comprising an initially opentopped box, a transparent scale-marked hemispherical dome mounted on topof the box, a pendulum assembly mounted in the box for'universalmovement about the center of the dome as an axis, said assemblyincluding an upstanding pointer and a depending weight, a sighting boreextending through said assembly from top to bottom, the box having acentral aperture in the bottom, and a transparent plate, having crosshairs therein, in register with said aperture; the point of intersectionof said cross hairs being vertically alined with the top center point ofthe dome.

"6. A mechanical, gravity actuated level comprising an initially opentopped box, a transparent scale-marked hemispherical dome mounted on topof the box, a pendulum assembly mounted in the box for universalmovement about the center of the dome as an axis, said assemblyincluding an upstanding pointer and a depending weight, a sighting boreextending through said assembly from top to bottom, the box having acentral aperture in the bottom, and a transparent plate, having crosshairs therein, in register with the aperture; the point of intersectionof said cross hairs being vertically alined with the top center point ofthe dome, and the box having feet thereon to support the bottom of thebox in clearance relation to the object on which the feet rest so as topermit light entry to said aperture.

FRED J. ALLGEO.

